Dead length collet chuck assemblies for holding a collet against longitudinal or axial displacement which would cause errors in the machining operation are well known. Examples of such collet chuck assemblies are disclosed in U.S. Pat. Nos. 628,730; 2,415,482; 4,690,415; and 5,480,164. U.S. Pat. No. 5,480,164, issued Jan. 2, 1996 to the present inventor and incorporated herein by reference, discloses a dead length collet chuck assembly in which a standard collet is threadedly received by a collet retaining ring secured to an interior surface of a chuck body. A longitudinally displaceable camming or closing sleeve surrounding the collet and having a tapered, internal camming surface operatively associated with a conical, exterior surface on the split forward end portion of the collet, compresses and releases the jaws of the collet in a well-known fashion. The longitudinally displaceable closing sleeve is connected to a longitudinally displaceable actuator by means of a series of longitudinal bolts which pass through oversized holes in the collet retaining ring. The bolts are threadedly secured to both the actuator and closing sleeve so that longitudinal displacement of the actuator in one direction or the other causes a substantially corresponding displacement of the closing sleeve.
Although the collet chuck assembly of U.S. Pat. No. 5,480,164 is an improvement over earlier collet chuck holders, it has been found that the cyclical tensile and compressive loads applied to the bolts interconnecting the collet closing sleeve and the collet sleeve actuator during the collet closing and opening sequences on occasion cause fatigue failure of the bolts.
Accordingly, it is an overall object of the present invention to provide a dead length collet chuck assembly having a collet actuator/closing sleeve interconnection that is not subject to fatigue failure.